Physical quantity detection element, physical quantity detection device, electronic apparatus, and moving object

ABSTRACT

A physical quantity detection element includes: a substrate; first and second fixed electrode portions on the substrate; a movable body on the upper portion of the substrate; and a beam on the movable body, the movable body includes a first movable body on a first side of the beam, and a second movable body on a second side of the beam, the first movable body includes a first movable electrode portion facing the first fixed electrode portion and a first mass portion disposed in an opposite direction of the beam from the first movable electrode portion, the second movable body includes a second movable electrode portion facing the second fixed electrode portion, a mass of the first movable body is greater than a mass of the second movable body, and a mass of the first mass portion is greater than a mass of the first movable electrode portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/504,894, filed on Oct. 2, 2014, which claims priority to JapanesePatent Application No. 2013-207963, filed on Oct. 3, 2013. Thedisclosures of the above applications are incorporated by reference intheir entireties.

BACKGROUND 1. Technical Field

The present invention relates to a physical quantity detection element,a physical quantity detection device, an electronic apparatus, and amoving object including the physical quantity detection element.

2. Related Art

In the related art, a physical quantity detection element which isconfigured based on a principle of a locker lever and detectscapacitance which changes according to physical quantity such asacceleration has been known as a method of detecting physical quantitysuch as acceleration in a vertical direction. For example,JP-T-2010-512527 discloses a micromachining type Z sensor (physicalquantity detection element) including a locker lever configured with atorsion spring, and a mass structure in which a seismic auxiliary massbody is provided on one side of the torsion spring and masses of bothsides of the torsion spring are different from each other. In thisphysical quantity detection element, when the physical quantity such asacceleration in the vertical direction is applied, the locker leverhaving the greater mass of the mass body is pressed down, andcapacitance formed between counter electrodes facing the mass bodychanges. The detection of the physical quantity such as acceleration isperformed by measuring the change in capacitance.

In the physical quantity detection element having the above-describedsystem, a penetration hole is provided on a movable body in order toprevent drag due to air generated between the movable body and asubstrate (squeeze film damping: hereinafter referred to as damping),when the movable body (mass structure) is displaced towards thesubstrate on which fixed electrodes (counter electrodes) are formed.However, in the physical quantity detection element disclosed inJP-T-2010-512527, since a gap (web width) close to the penetration holeprovided on a first mass portion (auxiliary mass body) is narrower thana gap close to the penetration hole provided on the movable body, thefirst mass portion is easily damaged when the impact is on the movablebody. A decrease in mass of the first mass portion causes a decrease insensitivity for detecting the physical quantity such as acceleration,and therefore miniaturization of the physical quantity detection elementis difficult.

SUMMARY

An advantage of some aspects of the invention is to solve at least apart of the problems described above, and the invention can beimplemented as the following forms or application examples.

Application Example 1

A physical quantity detection element according to this applicationexample includes: a substrate; a first fixed electrode portion and asecond fixed electrode portion provided on the substrate; a movable bodyprovided on the upper portion of the substrate; and a beam provided onthe movable body, in which the movable body includes a first movablebody on a first side of the movable body with respect to the beam, and asecond movable body on a second side of the movable body with respect tothe beam, the first movable body includes a first movable electrodeportion facing the first fixed electrode portion and a first massportion disposed in an opposite direction of the beam from the firstmovable electrode portion, the second movable body includes a secondmovable electrode portion facing the second fixed electrode portion, amass of the first movable body is greater than a mass of the secondmovable body, and a mass of the first mass portion is greater than amass of the first movable electrode portion.

According to this application example, since the mass of the firstmovable body is configured to be greater than the mass of the secondmovable body and the mass of the first mass portion is configured to begreater than the mass of the first movable electrode portion, it ispossible to provide a physical quantity detection element which canimprove the sensitivity for detecting physical quantity and reliabilityand realize miniaturization.

Application Example 2

In the physical quantity detection element according to the applicationexample described above, it is preferable that a thickness of the firstmass portion is equivalent to a thickness of the first movable electrodeportion.

According to this application example, by setting the mass per unit areaof the first mass portion to be greater than the mass per unit area ofthe first electrode portion in the movable body in which the thicknessof the first mass portion is equivalent to that of the first movableelectrode portion, it is possible to improve the sensitivity fordetecting physical quantity and reliability of the physical quantitydetection element. In addition, since the thickness of the first massportion is equivalent to that of the first movable electrode portion, itis possible to easily perform micromachining by etching or the like.

Application Example 3

In the physical quantity detection element according to the applicationexample described above, it is preferable that a thickness of the firstmass portion is greater than a thickness of the first movable electrodeportion and a thickness of the second movable electrode portion.

According to this application example, the thickness of the movable bodyis different between the first movable electrode portion and the secondmovable electrode portion, and the first mass portion. Since thethickness of the first mass portion is greater than that of the firstmovable electrode portion and the second movable electrode portion, themass of the first mass portion increases, and accordingly, torque fortwisting the beam increases and the rigidity of the first mass portionalso increases. Therefore, it is possible to improve the sensitivity fordetecting physical quantity and reliability of the physical quantitydetection element.

Application Example 4

In the physical quantity detection element according to the applicationexample described above, it is preferable that a plurality of firstpenetration holes are provided in the first movable electrode portion,and a plurality of second penetration holes are provided in the firstmass portion, and an average dimension of gaps between the secondpenetration holes adjacent to each other in a direction orthogonal tothe extension direction of the beam is greater than an average dimensionof gaps between the first penetration holes adjacent to each other in adirection orthogonal to the extension direction of the beam.

According to this application example, since the average dimension ofgaps between the second penetration holes adjacent to each other in adirection orthogonal to the extension direction of the beam is greaterthan the average dimension of gaps between the first penetration holesadjacent to each other in a direction orthogonal to the extensiondirection of the beam, the mass of the first mass portion increases, andaccordingly, the torque for twisting the beam increases and the rigidityof the first mass portion also increases. Therefore, it is possible toimprove the sensitivity for detecting physical quantity and reliabilityof the physical quantity detection element.

Application Example 5

In the physical quantity detection element according to the applicationexample described above, it is preferable that a plurality of firstpenetration holes are provided in the first movable electrode portion,and a plurality of second penetration holes are provided in the firstmass portion, and an average dimension of gaps between the secondpenetration holes adjacent to each other in a direction parallel withthe extension direction of the beam is greater than an average dimensionof gaps between the first penetration holes adjacent to each other in adirection parallel with the extension direction of the beam.

According to this application example, since the average dimension ofgaps between the second penetration holes adjacent to each other in adirection parallel with the extension direction of the beam is greaterthan the average dimension of gaps between the first penetration holesadjacent to each other in a direction parallel with the extensiondirection of the beam, the mass of the first mass portion increases, andaccordingly, the torque for twisting the beam increases and the rigidityof the first mass portion also increases. Therefore, it is possible toimprove the sensitivity for detecting physical quantity and reliabilityof the physical quantity detection element.

Application Example 6

In the physical quantity detection element according to the applicationexample described above, it is preferable that buffer portions areprovided on a surface of the first mass portion on the substrate side.

According to this application example, since the buffer portions areprovided on the first mass portion which may come in contact with thesubstrate due to great physical quantity applied to the movable body, itis possible to buffer an impact applied to the first mass portion. Sincethe mass of the buffer portions is added to the first mass portion, themass of the first mass portion increases and torque for twisting thebeam increases. Therefore, it is possible to improve the sensitivity fordetecting physical quantity and reliability of the physical quantitydetection element.

Application Example 7

In the physical quantity detection element according to the applicationexample described above, it is preferable that an electrode is providedon a surface of the first mass portion on the substrate side.

According to this application example, since a load of the electrode isadded to the first mass portion, the mass of the first mass portionincreases and torque for twisting the beam increases. In addition, sincethe hardness of aluminum or gold used as the electrode material is low,it is possible to buffer an impact applied to the first mass portion.Therefore, it is possible to improve the sensitivity for detectingphysical quantity and reliability of the physical quantity detectionelement.

Application Example 8

In the physical quantity detection element according to the applicationexample described above, it is preferable that, when the movable body isdivided into two by a center line in a direction orthogonal to anextension direction of the beam at an area ratio, masses of the dividedportions are equivalent to each other.

According to this application example, since the masses of the dividedportions obtained by dividing the movable body into two by a center linein the direction orthogonal to the extension direction of the beam areequivalent to each other, it is possible to cause the movable body toperform see-saw swinging using the beam as a fulcrum, while maintainingboth short sides parallel with the extension direction of the beam to behorizontal, when physical quantity such as acceleration in a verticaldirection is applied to the movable body. Accordingly, it is possible toprevent torsional swing (vibration) of the movable body and therefore itis possible to improve sensitivity for detecting physical quantity ofthe physical quantity detection element.

Application Example 9

In the physical quantity detection element according to the applicationexample described above, it is preferable that the movable body isprovided line-symmetrically with respect to a center line in a directionorthogonal to an extension direction of the beam.

According to this application example, since the movable body isprovided line-symmetrically with respect to the center line in thedirection orthogonal to an extension direction of the beam, the mass andthe damping received by the movable body (air drag) are alsosymmetrical. Accordingly, an effect of preventing torsional swing of themovable body increases, and therefore it is possible to improvesensitivity for detecting physical quantity of the physical quantitydetection element.

Application Example 10

A physical quantity detection device according to this applicationexample includes: the physical quantity detection element according tothe application example described above; and a detection circuit whichoutputs a signal according to physical quantity applied to the physicalquantity detection element.

According to this application example, it is possible to provide aphysical quantity detection device including a physical quantitydetection element with improved sensitivity for detecting physicalquantity and reliability.

Application Example 11

An electronic apparatus according to this application example includesthe physical quantity detection element according to the applicationexample described above.

According to this application example, it is possible to provide anelectronic apparatus including a physical quantity detection elementwith improved sensitivity for detecting physical quantity andreliability.

Application Example 12

A moving object according to this application example includes thephysical quantity detection element according to the application exampledescribed above.

According to this application example, it is possible to provide amoving object including a physical quantity detection element withimproved sensitivity for detecting physical quantity and reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a plan view schematically showing a physical quantitydetection element according to Embodiment 1.

FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1.

FIGS. 3A to 3D are cross-sectional views each schematically showing arelationship between an operation of a physical quantity detectionelement and capacitance.

FIG. 4 is a plan view schematically showing a physical quantitydetection element according to Embodiment 2.

FIG. 5 is a cross-sectional view taken along line A-A in FIG. 4.

FIG. 6 is a plan view schematically showing a physical quantitydetection element according to Modification Example 1.

FIG. 7 is a cross-sectional view taken along line A-A in FIG. 6.

FIG. 8 is a plan view schematically showing a physical quantitydetection element according to Modification Example 2.

FIG. 9 is a cross-sectional view taken along line A-A in FIG. 8.

FIG. 10 is a cross-sectional view showing an outline of a physicalquantity detection device including a physical quantity detectionelement.

FIG. 11 is a perspective view showing a configuration of a mobile type(or note type) personal computer as an electronic apparatus including aphysical quantity detection element.

FIG. 12 is a perspective view showing a mobile phone as an electronicapparatus including a physical quantity detection element.

FIG. 13 is a perspective view showing a digital still camera as anelectronic apparatus including a physical quantity detection element.

FIG. 14 is a perspective view showing a vehicle as a moving objectincluding a physical quantity detection element.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of the invention will be described withreference to the drawings. In each drawing hereinafter, scales of layersor members are different from the actual scales thereof, in order tohave recognizable sizes of the layers and the members.

Embodiment 1

FIG. 1 is a plan view schematically showing a physical quantitydetection element according to Embodiment 1. FIG. 2 is a cross-sectionalview taken along line A-A in FIG. 1. Herein, in FIGS. 1 and 2, and FIGS.3A to 9 which will be described later, an X axis, a Y axis, and a Z axisare shown as three axes orthogonal to each other, and a distal side ofan arrow shown in the drawings is set as a “positive side” and aproximal side thereof is set as a “negative side”, for convenience.Hereinafter, a direction parallel with the X axis is referred to as an“X axis direction”, a direction parallel with the Y axis is referred toas a “Y axis direction”, and a direction parallel with the Z axis isreferred to as a “Z axis direction”.

First, a schematic configuration of a physical quantity detectionelement according to Embodiment 1 will be described with reference toFIGS. 1 and 2.

A physical quantity detection element 1 of the embodiment can be used asan inertial sensor, for example. Specifically, the physical quantitydetection element can be used as a sensor (capacitance type accelerationsensor or capacitance type MEMS acceleration sensor) element formeasuring physical quantity such as acceleration in a vertical direction(Z axis direction).

As shown in FIGS. 1 and 2, the physical quantity detection element 1includes a substrate 10, a first fixed electrode portion 11 and a secondfixed electrode portion 12 provided on a main surface 10 a of thesubstrate 10, a movable body 20 which is provided with a gap interposedbetween the movable body and the substrate 10, through a support 14which is provided to stand in the positive Z axis direction from themain surface 10 a between the first fixed electrode portion 11 and thesecond fixed electrode portion 12 and a beam 16 supported by the support14. The beam 16 functions as a so-called torsion spring and rotatablysupports the movable body 20. The support 14 is configured with asupport 14 a which is integrally formed with the substrate 10 and asupport 14 b which is integrally formed with the movable body 20.

A material of the substrate 10 is not particularly limited, but in theembodiment, an insulating material including borosilicate glass is usedas a preferable example. The support 14 a provided on the substrate 10can be formed by performing micromachining such as photolithography andetching of the substrate 10.

The first fixed electrode portion 11 is positioned on the negative Xaxis direction side with respect to the support 14 a in a side view fromthe Y axis direction, and is provided in an area overlapped with a firstmovable electrode portion 21, which will be described later, provided onthe main surface 10 a of the substrate 10 in a plan view from the Z axisdirection.

The second fixed electrode portion 12 is positioned on the positive Xaxis direction side with respect to the support 14 a in a side view fromthe Y axis direction, and is provided in an area overlapped with asecond movable electrode portion 22, which will be described later,provided on the main surface 10 a of the substrate 10 in a plan viewfrom the Z axis direction.

For example, platinum (Pt), aluminum (Al), molybdenum (Mo), chrome (Cr),titanium (Ti), nickel (Ni), copper (Cu), silver (Ag), gold (Au) or analloy having the metal as a main component is used for the first fixedelectrode portion 11 and the second fixed electrode portion 12. Asputtering method, for example, is used for forming the first fixedelectrode portion 11 and the second fixed electrode portion 12 as films,and photolithography and etching, for example, are used for patterning(outer shape formation) thereof.

The movable body 20 is integrally formed with the support 14 b and thebeam 16 supported by the support 14 b, and is provided with a gapinterposed between the movable body and the substrate 10, through thesupports 14 a and 14 b and the beam 16. In the movable body 20, a firstmovable electrode portion 21 and a first mass portion 23 are provided inthis order in the negative X axis direction from the beam 16, and asecond movable electrode portion 22 is provided in the positive X axisdirection from the beam 16. In a plan view from the Z axis direction,the first movable electrode portion 21 is positioned in an areaoverlapped with the first fixed electrode portion 11, and the secondmovable electrode portion 22 is positioned in an area overlapped withthe second fixed electrode portion 12. In the description hereinafter,in the movable body 20, an area on the negative X axis direction from acenter line CL2 of the beam 16 is referred to as a first movable body 20a, and an area on the positive X axis direction from the center line CL2of the beam 16 is referred to as a second movable body 20 b.

The movable body 20 has a rectangular plate shape in a plan view fromthe Z axis direction, and in the embodiment, a dimension of the firstmass portion 23 in a thickness direction (Z axis direction) isequivalent to each dimension of the first movable electrode portion 21and the second movable electrode portion 22 in the thickness direction(Z axis direction). Therefore, it is possible to easily performmicromachining for forming the movable body 20. A material of themovable body 20, the support 14 b, and the beam 16 is not particularlylimited, and a conductive material including silicon is used, as apreferable example. It is possible to integrally form the movable body20, the support 14 b, and the beam 16 by micromachining such asphotolithography and etching. The conductive material is used for themovable body 20 in order to cause each of the first movable electrodeportion 21 and the second movable electrode portion 22 to have afunction as an electrode. The first movable electrode portion 21 and thesecond movable electrode portion 22 may be formed with a conductiveelectrode layer provided on a non-conductive substrate.

The movable body 20 is supported by the beam 16 and can rotate using thebeam 16 as a shaft. As the movable body 20 performs see-saw swing(inclination) using the beam 16 as a fulcrum, a gap (distance) betweenthe first movable electrode portion 21 and the first fixed electrodeportion 11 and a gap (distance) between the second movable electrodeportion 22 and the second fixed electrode portion 12 are changed. Thephysical quantity detection element 1 can change capacitance generatedbetween the first movable electrode portion 21 and the first fixedelectrode portion 11 and between the second movable electrode portion 22and the second fixed electrode portion 12, according to the inclinationof the movable body 20.

When acceleration in the vertical direction (for example, accelerationof gravity) is applied to the movable body 20, a rotation moment (momentof force) is generated in each of the first movable body 20 a and thesecond movable body 20 b. Herein, when the rotation moment (for example,counterclockwise rotation moment) of the first movable body 20 a, andthe rotation moment (for example, clockwise rotation moment) of thesecond movable body 20 b are balanced, a change in inclination of themovable body 20 does not occur, and it is difficult to detect theacceleration. Accordingly, the movable body 20 is designed so that therotation moment of the first movable body 20 a and the rotation momentof the second movable body 20 b are not balanced and a change ininclination of the movable body 20 occurs, when the acceleration in thevertical direction is applied thereto.

In the physical quantity detection element 1, the first movable body 20a and the second movable body 20 b have different masses from eachother, by disposing the beam 16 in a position deviated from a center ofgravity of the movable body 20 in the X axis direction (bydifferentiating a distance from the beam 16 to an end surface of thefirst movable body 20 a, from a distance from the beam to an end surfaceof the second movable body 20 b). That is, in the movable body 20, onemovable body (first movable body 20 a) and the other movable body(second movable body 20 b) have different mass from each other, with thecenter line CL2 of the beam 16 as a starting point. In the example shownin the drawing, the distance from the beam 16 to the end surface of thefirst movable body 20 a in the negative X axis direction is greater thanthe distance from the beam 16 to the end surface of the second movablebody 20 b in the positive X axis direction. In addition, a thickness ofthe first movable body 20 a is substantially equivalent to a thicknessof the second movable body 20 b. Accordingly, the mass of the firstmovable body 20 a is greater than the mass of the second movable body 20b. As described above, since the first movable body 20 a and the secondmovable body 20 b have different mass from each other, it is possible tocause the rotation moment of the first movable body 20 a and therotation moment of the second movable body 20 b which are generated whenthe acceleration in the vertical direction is applied to the movablebody 20, not to be balanced. Therefore, the movable body 20 can beinclined when the acceleration in the vertical direction is appliedthereto.

In the movable body 20, capacitance (variable capacitance) C1 isconfigured between the first movable electrode portion 21 and the firstfixed electrode portion 11. In addition, capacitance (variablecapacitance) C2 is configured between the second movable electrodeportion 22 and the second fixed electrode portion 12. The capacitance C1changes depending on the gap (distance) between the first movableelectrode portion 21 and the first fixed electrode portion 11, and thecapacitance C2 changes depending on the gap (distance) between thesecond movable electrode portion 22 and the second fixed electrodeportion 12.

For example, the capacitance items C1 and C2 have capacitance valuessubstantially equivalent to each other, in a horizontal state of themovable body 20 with respect to the substrate 10. In detail, in a planview from the Z axis direction, an area in which the first movableelectrode portion 21 and the first fixed electrode portion 11 areoverlapped with each other, and an area in which the second movableelectrode portion 22 and the second fixed electrode portion 12 areoverlapped with each other are equivalent to each other, and in a sideview from the Y axis direction, the gap between the first movableelectrode portion 21 and the first fixed electrode portion 11 and thegap between the second movable electrode portion 22 and the second fixedelectrode portion 12 are equivalent to each other, and therefore, thecapacitance values of capacitance items C1 and C2 are equivalent to eachother.

In addition, when the acceleration in the vertical direction is appliedto the movable body 20 and the movable body 20 is inclined with the beam16 as a shaft, the capacitance values of capacitance items C1 and C2change depending on the inclination of the movable body 20. Since thegap between the first movable electrode portion 21 and the first fixedelectrode portion 11 and the gap between the second movable electrodeportion 22 and the second fixed electrode portion 12 are different fromeach other in a state where the movable body 20 is inclined, thecapacitance values of capacitance items C1 and C2 are also differentfrom each other.

Herein, a relationship between an operation of the physical quantitydetection element and the capacitance will be described in detail, withreference to FIGS. 3A to 3D. FIGS. 3A to 3D are cross-sectional viewseach schematically showing an operation of the physical quantitydetection element, and the configurations not necessary for thedescription of the operation are omitted in the drawings. Herein, it isassumed that the movable body is a plate-shaped rectangle having auniform thickness and a penetration hole which will be described lateris not provided therein, for convenience of description.

FIG. 3A is a diagram illustrating a case in which acceleration αu in thepositive Z axis direction is applied to the physical quantity detectionelement 1 in which the movable body 20 is positioned in a substantiallyhorizontal state with respect to the substrate 10.

The movable body 20 is a plate-shaped rectangle having a uniformthickness (dimension in the Z axis direction). The first movable body 20a has mass m1 and a center of gravity G1 thereof is positioned at adistance r1 in the negative X axis direction from a center Q of the beam16 rotatably supported by the support 14. The second movable body 20 bhas mass m2 and a center of gravity G2 thereof is positioned at adistance r2 in the positive X axis direction from the center Q of thebeam 16. Since the first movable body 20 a has a rectangular shapehaving a longer side in the X axis direction than that of the secondmovable body 20 b, the mass m1 of the first movable body 20 a is greaterthan the mass m2 of the second movable body 20 b, and the distance r1 atwhich the center of gravity G1 of the first movable body 20 a ispositioned, is longer than the distance r2 at which the center ofgravity G2 of the second movable body 20 b is positioned.

When the acceleration αu towards the positive Z axis direction from thenegative Z axis direction is applied with respect to the physicalquantity detection element 1, a first rotation moment Nu1 correspondingto the product of the mass m1, the acceleration αu, and the distance r1acts clockwise with the center Q of the beam 16 as a rotation shaft, inthe first movable body 20 a. Meanwhile, a second rotation moment Nu2corresponding to the product of the mass m2, the acceleration αu, andthe distance r2 is operated to the second movable body 20 bcounterclockwise with the center Q of the beam 16 as a rotation shaft.Since the mass m1 of the first movable body 20 a is greater than themass m2 of the second movable body 20 b and the distance r1 at which thecenter of gravity G1 of the first movable body 20 a is positioned islonger than the distance r2 at which the center of gravity G2 of thesecond movable body 20 b is positioned, the first rotation moment Nu1operated to the first movable body 20 a is greater than the secondrotation moment Nu2 operated to the second movable body 20 b.

Accordingly, as shown in FIG. 3B, torque Nu corresponding to adifference between the first rotation moment Nu1 (see FIG. 3A) and thesecond rotation moment Nu2 (see FIG. 3A) is operated to the beam 16clockwise with the center Q of the beam 16 as a rotation shaft, and themovable body 20 is inclined clockwise. Thus, the gap between the firstmovable electrode portion 21 of the first movable body 20 a and thefirst fixed electrode portion 11 increases (is widened), and thecapacitance value of the capacitance C1 between the first movableelectrode portion 21 and the first fixed electrode portion 11 decreases.Meanwhile, the second movable electrode portion 22 of the second movablebody 20 b and the second fixed electrode portion 12 decreases (isnarrowed), and the capacitance value of the capacitance C2 between thesecond movable electrode portion 22 and the second fixed electrodeportion 12 increases.

FIG. 3C is a diagram illustrating a case in which acceleration αd in thenegative Z axis direction is applied to the physical quantity detectionelement 1 in which the movable body 20 is positioned in a substantiallyhorizontal state with respect to the substrate 10.

When the acceleration αd towards the negative Z axis direction from thepositive Z axis direction is applied with respect to the physicalquantity detection element 1, a first rotation moment Nd1 correspondingto the product of the mass m1, the acceleration αu, and the distance r1is operated to the first movable body 20 a counterclockwise with thecenter Q of the beam 16 as a rotation shaft. Meanwhile, a secondrotation moment Nd2 corresponding to the product of the mass m2, theacceleration αd, and the distance r2 is operated to the second movablebody 20 b clockwise with the center Q of the beam 16 as a rotationshaft. Since the mass m1 of the first movable body 20 a is greater thanthe mass m2 of the second movable body 20 b and the distance r1 at whichthe center of gravity G1 of the first movable body 20 a is positioned islonger than the distance r2 at which the center of gravity G2 of thesecond movable body 20 b is positioned, the first rotation moment Nd1operated to the first movable body 20 a is greater than the secondrotation moment Nd2 operated to the second movable body 20 b.

Accordingly, as shown in FIG. 3D, torque Nd corresponding to adifference between the first rotation moment Nd1 (see FIG. 3C) and thesecond rotation moment Nd2 (see FIG. 3C) is operated to the beam 16counterclockwise with the center Q of the beam 16 as a rotation shaft,and the movable body 20 is inclined counterclockwise. Thus, the gapbetween the first movable electrode portion 21 of the first movable body20 a and the first fixed electrode portion 11 is decreased (isnarrowed), and the capacitance value of the capacitance C1 between thefirst movable electrode portion 21 and the first fixed electrode portion11 is increased. Meanwhile, the second movable electrode portion 22 ofthe second movable body 20 b and the second fixed electrode portion 12is increased (is widened), and the capacitance value of the capacitanceC2 between the second movable electrode portion 22 and the second fixedelectrode portion 12 is decreased.

The physical quantity detection element 1 can significantly incline themovable body 20, by increasing the torque Nu and Nd operated to the beam16. Accordingly, the fluctuation in the capacitance values of thecapacitance C1 and C2 is great, and thus it is possible to improvesensitivity for detecting the physical quantity of the physical quantitydetection element 1.

As described above, the increase in the torque Nu and Nd can be realizedby setting the mass m1 of the first movable electrode portion 21 to begreater than the mass m2 of the second movable electrode portion 22or/and setting the distance r1 between the center of gravity G1 of thefirst movable body 20 a and the center Q of the beam 16 to be longerthan the distance r2 between the center of gravity G2 of the secondmovable body 20 b and the center Q of the beam 16. Therefore, in thephysical quantity detection element 1, it is possible to improve thesensitivity for detecting the physical quantity, by increasing thedifference between the mass m1 of the first movable electrode portion 21and the mass m2 of the second movable electrode portion 22 or/andincreasing the difference between the distance r1 between the center ofgravity G1 of the first movable body 20 a and the center Q of the beam16 and the distance r2 between the center of gravity G2 of the secondmovable body 20 b and the center Q of the beam 16. In addition, in thephysical quantity detection element 1, there is a method of improvingthe sensitivity for detecting the physical quantity, by narrowing awidth of the beam 16 which functions as a torsion spring in the X axisdirection, in order to decrease toughness of the spring, and increasethe inclination of the movable body 20.

Next, by returning to FIG. 1 and FIG. 2, a penetration hole provided onthe movable body will be described.

When the acceleration in the vertical direction is applied to themovable body 20 and the movable body 20 swings, the damping (motion forstopping motion of the movable body, flow resistance) generated due togaseous viscosity decreases, and accordingly, first penetration holes 26and second penetration holes 27 which penetrate through the movable body20 in the Z axis direction are provided on the movable body 20. Theplurality of first penetration holes 26 are provided on the firstmovable electrode portion 21 and the second movable electrode portion22, and the plurality of second penetration holes 27 are provided on thefirst mass portion 23. In the embodiment, the first penetration holes 26having the same shape as each other and disposed in matrix to have 3rows and 3 columns, are provided on the first movable electrode portionand the second movable electrode portion 22, and the plurality of secondpenetration holes 27 having the same shape as each other and disposed inmatrix to have 2 rows and 2 columns, are provided on the first massportion 23. The plurality of first penetration holes 26 and the secondpenetration holes 27 may have different shapes from each other. Inaddition, positions for disposing the first penetration holes 26 and thesecond penetration holes 27 or the number thereof can be freely set.

In the embodiment, since mass per unit area of the first mass portion 23(value obtained by dividing the mass of the first mass portion 23 by thearea of the first mass portion 23) is greater than mass per unit area ofthe first movable electrode portion 21 (value obtained by dividing themass of the first movable electrode portion 21 by the area of the firstmovable electrode portion 21), it is possible to improve sensitivity fordetecting the physical quantity of the physical quantity detectionelement 1. In the specific description with reference to FIG. 1 and FIG.3A, the mass per unit area of the first mass portion 23 is set to begreater than the mass per unit area of the first movable electrodeportion 21 while the mass m1 of the first movable body 20 a ismaintained as it is, and accordingly, the position of the center ofgravity G1 of the first movable body 20 a is moved in the negative Xaxis direction. Accordingly, the difference between the distance r1between the center of gravity G1 of the first movable body 20 a and thecenter Q of the beam 16, and the distance r2 between the center ofgravity G2 of the second movable body 20 b and the center Q of the beam16 is set to be great, and thus it is possible to improve sensitivityfor detecting the physical quantity of the physical quantity detectionelement 1. In general, the increase in mass relates to the improvementof rigidity, and accordingly the rigidity of the first mass portion 23is higher than the rigidity of the first movable electrode portion 21,and thus it is possible to prevent damage to the first mass portion 23when the end portion of the first mass portion 23 comes in contact withthe substrate 10.

In the embodiment, the plurality of second penetration holes areprovided on the first mass portion, and the plurality of firstpenetration holes are provided on the first movable electrode portion.Since an average dimension of gaps L2 of the second penetration holes 27adjacent to each other in a direction (X axis direction) orthogonal tothe beam 16 is greater than an average dimension of gaps L1 of the firstpenetration holes 26 adjacent to each other in the X axis direction, itis possible to improve sensitivity for detecting physical quantity ofthe physical quantity detection element 1. In the specific descriptionwith reference to FIG. 1 and FIG. 3A, in general, as a dimension of thepenetration holes of the objects adjacent to each other in which theplurality of penetration holes are provided increases, the mass of theobject increases. Accordingly, since the mass of the first mass portion23 is greater than the mass of the first movable electrode portion 21,the position of the center of gravity G1 of the first movable body 20 ais moved in the negative X axis direction. Accordingly, since thedifference between the distance r1 at which the center of gravity G1 ofthe first movable body 20 a is positioned, and the distance r2 at whichthe center of gravity G2 of the second movable body 20 b is positionedcan be set to be great, it is possible to improve sensitivity fordetecting the physical quantity of the physical quantity detectionelement 1. Since the mass of the first mass portion 23 is greater thanthe mass of the first movable electrode portion 21, it is possible toprevent damage to the first mass portion 23 when the end portion of thefirst mass portion 23 comes in contact with the substrate 10.

For example, the width in the X axis direction of the beam 16 whichfunctions as a torsion spring is set to be smaller than the averagedimension of the gaps L2 of the second penetration holes 27 adjacent toeach other in the X axis direction, in order to decrease toughness ofthe spring, and thus inclination of the movable body 20 can be great.Therefore, it is possible to improve sensitivity for detecting thephysical quantity of the physical quantity detection element 1.

In the embodiment, the plurality of second penetration holes areprovided on the first mass portion, and the plurality of firstpenetration holes are provided on the first movable electrode portion.Since an average dimension of gaps R2 of the second penetration holes 27adjacent to each other in a direction (Y axis direction) parallel withthe beam 16 is greater than an average dimension of gaps R1 of the firstpenetration holes 26 adjacent to each other in the Y axis direction, itis possible to improve sensitivity for detecting physical quantity ofthe physical quantity detection element 1. Accordingly, since the massof the first mass portion 23 is greater than the mass of the firstmovable electrode portion 21, the position of the center of gravity G1of the first movable body 20 a is moved in the negative X axisdirection. Accordingly, the difference between the distance r1 betweenthe center of gravity G1 of the first movable body 20 a and the center Qof the beam 16, and the distance r2 between the center of gravity G2 ofthe second movable body 20 b and the center Q of the beam 16 is set tobe great, and thus it is possible to improve sensitivity for detectingthe physical quantity of the physical quantity detection element 1.Since the mass of the first mass portion 23 is greater than the mass ofthe first movable electrode portion 21, it is possible to prevent damageto the first mass portion 23 when the end portion of the first massportion 23 comes in contact with the substrate 10.

In the embodiment, when the movable body 20 is divided into two by acenter line CL1 in a direction (X axis direction) orthogonal to anextension direction of the beam 16 at an area ratio, the masses of thedivided portions are equivalent to each other. In a plan view from the Zaxis direction, even when the size or disposition of the firstpenetration holes 26 and the second penetration holes 27 are differentfrom each other and the first penetration holes and the secondpenetration holes are not symmetrical to each other, the mass of an area20 c and the mass of an area 20 d are equivalent to each other, andaccordingly, it is possible to cause the see-saw swing of the movablebody while maintaining horizontally two sides parallel with the Y axisof the movable body 20, when the acceleration in the Z axis direction isapplied to the movable body 20. Thus, it is possible to preventtorsional swing of the movable body 20, and therefore it is possible toimprove detection accuracy of the physical quantity detection element 1.

In the embodiment, the movable body 20 is provided line-symmetricallywith respect to the center line CL1. Since the first penetration holes26 and the second penetration holes 27 are provided on the movable body20 with respect to the center line CL2, the masses of the area 20 c andthe area 20 d are equivalent to each other and damping (air drag)received in each area is also symmetrical to each other. Therefore, itis advantageous to prevent torsional swing of the movable body 20 and toimprove detection accuracy of the physical quantity detection element 1.

In the embodiment, the configuration in that the movable body 20 isprovided through the support 14 which is provided to stand in thepositive Z axis direction from the main surface 10 a between the firstfixed electrode portion 11 and the second fixed electrode portion 12 andthe beam 16 supported by the support 14 is described, but it is notlimited to this configuration. For example, a frame-shaped supportingbody which surrounds the outer periphery of the movable body may beprovided to have a predetermined gap with the movable body, in a planview from the Z axis direction, and the movable body may be configuredto be supported by a beam extended in the Y axis direction from thesupport provided on the supporting body.

As described above, according to the physical quantity detection element1 of the embodiment, the following effects can be obtained.

At least one average dimension of the adjacent gaps L2 and R2 of theplurality of second penetration holes 27 provided on the first massportion 23 is greater than the average dimension of the adjacent gaps L1and/or R1 of the plurality of first penetration holes 26 provided on thefirst movable electrode portion 21. Since the movable body 20 has auniform thickness, the mass of the first mass portion 23 is greater thanthe mass of the first movable electrode portion 21, and the position ofthe center of gravity G1 of the first movable body 20 a is moved in thenegative X axis direction. Accordingly, the difference between thedistance r1 between the center of gravity G1 of the first movable body20 a and the center Q of the beam 16, and the distance r2 between thecenter of gravity G2 of the second movable body 20 b and the center Q ofthe beam 16 is set to be great, and thus it is possible to improvesensitivity for detecting the physical quantity of the physical quantitydetection element 1. That is, it is possible to realize miniaturizationwhile maintaining detection sensitivity. Since the rigidity of the firstmass portion 23 is higher than the rigidity of the first movableelectrode portion 21, it is possible to prevent damage to the first massportion 23 when the end portion of the first mass portion 23 comes incontact with the substrate 10. Therefore, it is possible to provide thephysical quantity detection element 1 which can improve detectionsensitivity and reliability and realize miniaturization.

Embodiment 2

FIG. 4 is a plan view schematically showing a physical quantitydetection element according to Embodiment 2. FIG. 5 is a cross-sectionalview taken along line A-A in FIG. 4.

The physical quantity detection element according to the embodiment willbe described with reference to the drawings. The same reference numeralsare used for the same constituent elements as those in Embodiment 1, andthe overlapped description will be omitted. The physical quantitydetection element of the embodiment is different from the configurationof Embodiment 1, in that a movable body having different thicknesses ofa first mass portion and a first movable electrode portion is provided.

As shown in FIG. 4 and FIG. 5, a physical quantity detection element 2includes the substrate 10, the first fixed electrode portion 11 and thesecond fixed electrode portion 12 provided on the main surface 10 a ofthe substrate 10, a movable body 30 which is provided with a gapinterposed between the movable body and the substrate 10, through thesupport 14 which is provided to stand in the positive Z axis directionfrom the main surface 10 a between the first fixed electrode portion 11and the second fixed electrode portion 12 and the beam 16 supported bythe support 14.

The movable body 30 is integrally formed with the support 14 b and thebeam 16 supported by the support 14 b, and is provided with a gapinterposed between the movable body and the substrate 10, through thesupports 14 a and 14 b and the beam 16. In the movable body 30, a firstmovable electrode portion 31 and a first mass portion 33 are provided inthis order in the negative X axis direction from the beam 16, and asecond movable electrode portion 32 is provided in the positive X axisdirection from the beam 16. In the description hereinafter, in themovable body 30, an area on the negative X axis direction from a centerline CL2 of the beam 16 is referred to as a first movable body 30 a, andan area on the positive X axis direction from the center line CL2 of thebeam 16 is referred to as a second movable body 30 b.

The movable body 30 has a rectangular plate shape in a plan view fromthe Z axis direction, and in the embodiment, a dimension of the firstmass portion 33 in a thickness direction (Z axis direction) is greaterthan each dimension of the first movable electrode portion 31 and thesecond movable electrode portion 32 in the thickness direction (Z axisdirection). Accordingly, the mass of the first mass portion 33increases, and thus the position of the center of gravity of the firstmovable body 30 a is moved in the negative X axis direction.Accordingly, the difference between the distance r1 between the centerof gravity G1 of the first movable body 30 a and the center Q of thebeam 16, and the distance r2 between the center of gravity G2 of thesecond movable body 30 b and the center Q of the beam 16 is set to begreat, and thus it is possible to improve sensitivity for detecting thephysical quantity of the physical quantity detection element 2. Sincethe mass of the first mass portion 33 is greater than the mass of thefirst movable electrode portion 31, it is possible to prevent damage tothe first mass portion 33 when the end portion of the first mass portion33 comes in contact with the substrate 10.

In the embodiment, the configuration of the movable body 30 hasdifferent thicknesses by setting a boundary of the first mass portion 33and the first movable electrode portion 31, but it is not limited tothis configuration. For example, the thickness of the first movable body30 a may sequentially increase in a stepwise manner or may be increasedgently, from the positive X axis direction towards the negative X axisdirection.

As described above, according to the physical quantity detection element2 of the embodiment, the following effects can be obtained, in additionto the effects in Embodiment 1.

The physical quantity detection element 2 includes the movable body 30having different thicknesses of the first mass portion 33 and the firstmovable electrode portion 31. The thickness of the first mass portion 33is greater than the thickness of the first movable electrode portion 31,and when the mass of the first movable body 30 a increases, the positionof the center of gravity moves in the negative X axis direction.Accordingly, it is possible to further improve sensitivity for detectingthe physical quantity of the physical quantity detection element 2. Thatis, it is possible to realize miniaturization while maintainingdetection sensitivity. Since the rigidity of the first mass portion 33is higher than the rigidity of the first movable electrode portion 31,it is possible to prevent damage to the first mass portion 33 when theend portion of the first mass portion 33 comes in contact with thesubstrate 10. Therefore, it is possible to provide the physical quantitydetection element 2 which can improve detection sensitivity andreliability and realize miniaturization.

The invention is not limited to the embodiments described above, andvarious modifications or improvements can be added to the embodimentsdescribed above.

In Embodiment 1, as shown in FIG. 1, the configuration in which theadjacent gaps of the plurality of second penetration holes 27 providedon the first mass portion 23 are set to be greater than the adjacentgaps of the plurality of first penetration holes 26 provided on thefirst movable electrode portion 21, in order to increase the mass of thefirst movable body 20 a, and the position of the center of gravity ischanged in the negative X axis direction, and it is not limited to thisconfiguration. Hereinafter, modification examples will be described.

Modification Example 1

FIG. 6 is a plan view schematically showing a physical quantitydetection element according to Modification Example 1. FIG. 7 is across-sectional view taken along line A-A in FIG. 6.

Hereinafter, a physical quantity detection element 3 according toModification Example 1 will be described. The same reference numeralsare used for the same constituent elements as those in Embodiment 1, andthe overlapped description will be omitted.

In the physical quantity detection element 3, buffer portions 50 havingmass are provided on the surface of two corners formed on the first massportion 23 on the substrate 10 side, in a plan view from the Z axisdirection. As a material of the buffer portions 50, silicone havingflexibility is used, in order to absorb an impact when the end portionof the first mass portion 23 comes in contact with the substrate 10.Accordingly, the mass of the first movable body 20 a increases, and theposition of the center of gravity is moved in the negative X axisdirection, and therefore the same operation effects as those in theembodiments can be obtained. In the modification example, the physicalquantity detection element includes the buffer portion 50 havingflexibility, and therefore it is possible to provide the physicalquantity detection element 3 with further improved reliability.

The shape or the number of the buffer portions 50 is not particularlylimited, as long as the buffer portions include a part of an area wherethe first mass portion 23 may come in contact with the substrate 10.Since the buffer portions 50 receive an impact, the buffer portions aredesirably provided on an area not including the second penetration holes27, from a viewpoint of reliability.

Modification Example 2

FIG. 8 is a plan view schematically showing a physical quantitydetection element according to Modification Example 2. FIG. 9 is across-sectional view taken along line A-A in FIG. 8.

A physical quantity detection element 4 according to ModificationExample 2 will be described. The same reference numerals are used forthe same constituent elements as those in Embodiment 1, and theoverlapped description will be omitted.

In the physical quantity detection element 4, an electrode 80 isprovided on the surface of the first mass portion 23 on the substrate 10side. By using a metal material having high specific gravity for theelectrode 80, it is possible to efficiently increase the mass of thefirst mass portion 23. Accordingly, the mass of the first movable body20 a increases and the position of the center of gravity is moved in thenegative X axis direction, and therefore the same operation effects asthose in the embodiments can be obtained. In addition, an impact whenthe end portion of the first mass portion 23 comes in contact with thesubstrate 10 can be absorbed by using a metal material having lowhardness for the electrode 80, and therefore it is possible to providethe physical quantity detection element 4 with further improvedreliability.

Physical Quantity Detection Device

Next, a physical quantity detection device to which the physicalquantity detection element 1 according to the invention is applied willbe described. FIG. 10 is a cross-sectional view showing an outline of aphysical quantity detection device 100 including the physical quantitydetection element 1.

The physical quantity detection element 1 covered with a cover 90 and anIC chip are mounted on a bottom surface of an interposer (IP) substrate110, and the physical quantity detection device 100 is further coveredwith a mold resin 120.

The physical quantity detection element 1 is configured with the firstfixed electrode portion 11 and the second fixed electrode portion 12provided on the substrate 10, the movable body 20, and the like. Thefirst fixed electrode portion 11 and the second fixed electrode portion12, the movable body 20, and the substrate 10 are electrically connectedwith each other with a wire (not shown). The material of the cover 90 isnot particularly limited, and in the physical quantity detection device100, a conductive material including silicon which can be easilyprocessed is used, as a preferable example. The cover 90 is bonded tothe substrate 10 in which borosilicate glass is used, by anodic bonding.A cavity 160 of the physical quantity detection element 1 covered withthe cover 90 is preferably in an inert gas atmosphere such as nitrogen.

A material such as glass fibers-containing epoxy is used for the IPsubstrate 110, and an external connection terminal and a wire (notshown) are formed therein. The substrate 10 of the physical quantitydetection element 1 and the IC chip 130 are bonded to each other andsupported on the IP substrate 110, through a fixed member 140 such as anadhesive. The material of the fixed member 140 is not particularlylimited, and a composite resin including an epoxy resin as a base resincan be used. The IC chip 130 is electrically connected to the wires (notshown) formed on the substrate 10 and the IP substrate 110, through awire 150 such as Au (gold). The IC chip 130 includes a detection circuitfor outputting the physical quantity such as the acceleration applied tothe physical quantity detection element 1.

Lastly, a surface of the IP substrate 110 on which the physical quantitydetection element 1 and the like are mounted is covered with the moldresin 120, and accordingly the physical quantity detection device 100can be configured.

As described above, since the miniaturized physical quantity detectionelement 1 with the improved detection sensitivity of the physicalquantity and reliability is used in the physical quantity detectiondevice 100, it is possible to provide the miniaturized physical quantitydetection device 100 having high detection sensitivity and highreliability.

Electronic Apparatus

Next, an electronic apparatus including the physical quantity detectionelement 1 or the physical quantity detection device 100 according to theembodiment of the invention will be described with reference to FIG. 11to FIG. 13. In the description, an example using the physical quantitydetection element 1 is shown.

FIG. 11 is a perspective view showing an outline of a configuration of amobile type (or note type) personal computer 1100 as the electronicapparatus including the physical quantity detection element 1 accordingto Embodiment 1 of the invention. In the drawing, a personal computer1100 is configured with a main body unit 1104 including a keyboard 1102and a display unit 1106 including a display unit 1000, and the displayunit 1106 is rotatably supported with respect to the main body unit 1104through a hinge structure portion. The physical quantity detectionelement 1 which functions as an acceleration sensor is embedded in sucha personal computer 1100.

FIG. 12 is a perspective view showing an outline of a configuration of amobile phone 1200 (including PHS) as the electronic apparatus includingthe physical quantity detection element 1 according to Embodiment 1 ofthe invention. In the drawing, the mobile phone 1200 includes aplurality of operation buttons 1202, an earpiece 1204, and a mouthpiece1206, and a display unit 1000 disposed between the operation buttons1202 and the earpiece 1204. The physical quantity detection element 1which functions as an acceleration sensor or the like is embedded insuch a mobile phone 1200.

FIG. 13 is a perspective view showing an outline of a configuration of adigital still camera 1300 as the electronic apparatus including thephysical quantity detection element 1 according to Embodiment 1 of theinvention. The drawing also simply shows connection to an externaldevice. Herein, the digital still camera 1300 generates an imagingsignal (image signal) by performing photoelectric conversion of alightimage of a subject by an imaging device such as charge coupled device(CCD), whereas a film camera of the related art exposes a silver-halidephoto film by a light image of a subject.

A display unit 1000 is provided on a rear surface of a case (body) 1302of the digital still camera 1300 and has a configuration of performing adisplay based on the imaging signal by the CCD, and the display unit1000 functions as a finder for displaying a subject as an electronicimage. A light receiving unit 1304 including an optical lens (opticalimaging system) or the CCD is provided on a front surface side of thecase 1302 (back surface side in the drawing).

When a photographer confirms a subject image displayed on the displayunit 1000 and presses a shutter button 1306, an imaging signal of CCD atthat point in time is transmitted and stored in a memory 1308. In thedigital still camera 1300, a video signal output terminal 1312 and adata communication input and output terminal 1314 are provided on a sidesurface of the case 1302. As shown in the drawing, a television monitor1430 is connected to the video signal output terminal 1312 and apersonal computer 1440 is connected to the data communication input andoutput terminal 1314, respectively if necessary. In addition, theimaging signal stored in the memory 1308 is output to the televisionmonitor 1430 or the personal computer 1440 by a predetermined operation.The physical quantity detection element 1 which functions as anacceleration sensor or the like is embedded in such a digital stillcamera 1300.

In addition to the personal computer 1100 (mobile type personalcomputer) shown in FIG. 11, the mobile phone 1200 shown in FIG. 12, andthe digital still camera 1300 shown in FIG. 13, the physical quantitydetection element 1 according to Embodiment 1 of the invention can beapplied to an electronic apparatus such as an ink jet type dischargingapparatus (for example, ink jet printer), a laptop type personalcomputer, a television, a video camera, a video camera recorder, a carnavigation device, a pager, an electronic organizer (includingcommunication function), an electronic dictionary, a calculator, anelectronic game device, a word processer, a work station, a video phone,a security monitor, electronic binoculars, a POS terminal, medicalequipment (for example, an electronic thermometer, a blood pressuremeter, a blood glucose meter, an ECG measuring device, an ultrasounddiagnostic device, an electronic endoscope), a fishfinder, a variety ofmeasurement equipment, a meter (for example, a meter for vehicles,aircraft, or a ship), a flight simulator, or the like.

Moving Object

FIG. 14 is a perspective view schematically showing a vehicle as anexample of a moving object. The physical quantity detection element 1according to Embodiment 1 is embedded in a vehicle 1500. For example, asshown in the drawing, the physical quantity detection element 1 isembedded in the vehicle 1500 as a moving object and an electroniccontrol unit 1510 which controls such as tires is embedded in a vehiclebody. The physical quantity detection element 1 can also be widelyapplied to an electronic control unit (ECU) such as a keyless entry, animmobilizer, a car navigation system, a car air conditioner, anti-lockbrake system (ABS), an air bag, a tire pressure monitoring system(TPMS), an engine control, a battery charge monitor of a hybrid car oran electric car, or a vehicle body attitude control unit.

What is claimed is:
 1. A physical quantity detection element comprising: a substrate; a first fixed electrode that is provided on a main surface of the substrate; a second fixed electrode that is provided on the main surface of the substrate, a first side of the first fixed electrode being directly adjacent to a second side of the second fixed electrode via a middle part of the main surface of the substrate; and a movable body that is provided above the main surface of the substrate, the movable body being configured with: a first movable electrode that faces the first fixed electrode via a gap in a plan view; a second movable electrode that faces the second fixed electrode via a gap in the plan view, each of the first and second movable electrodes having a plurality of first through holes; a beam that extends in a first direction, the beam being provided between the first and second movable electrodes, the beam facing the middle part of the main surface of the substrate in the plan view, the movable body being configured to move with respect to the beam relative to the main surface of the substrate; and a movable mass that extends from an end of the first movable electrode in a second direction away from the beam in the plan view, the second direction being perpendicular to the first direction, the movable mass having a plurality of second through holes, wherein when a distance between adjacent two of the plurality of first through holes in the first direction in the plan view is R1, a distance between adjacent two of the plurality of first though holes in the second direction in the plan view is L1, a distance between adjacent two of the plurality of second though holes in the first direction in the plan view is R2, and a distance between adjacent two of the plurality of second through holes in the second direction in the plan view is L2, at least one of: R1<R2; and L1<L2 is satisfied.
 2. The physical quantity detection element according to claim 1, wherein a thickness of the movable mass is equivalent to a thickness of the first movable electrode.
 3. The physical quantity detection element according to claim 1, wherein a thickness of the movable mass is greater than a thickness of the first movable electrode.
 4. The physical quantity detection element according to claim 1, wherein a buffer is provided on a surface of the movable mass facing the main surface of the substrate.
 5. The physical quantity detection element according to claim 2, wherein an electrode is provided on a surface of the movable mass facing the main surface of the substrate.
 6. The physical quantity detection element according to claim 1, wherein when the movable body is divided into two by a center line in the second direction at an area ratio, masses of the divided portions are equivalent to each other.
 7. The physical quantity detection element according to claim 1, wherein the movable body is provided line-symmetrically with respect to a center line in the second direction in the plan view.
 8. A physical quantity detection device comprising: the physical quantity detection element according to claim 1; and an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element.
 9. A physical quantity detection device comprising: the physical quantity detection element according to claim 2; and an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element.
 10. A physical quantity detection device comprising: the physical quantity detection element according to claim 3; and an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element.
 11. A physical quantity detection device comprising: the physical quantity detection element according to claim 4; and an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element.
 12. A physical quantity detection device comprising: the physical quantity detection element according to claim 5; and an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element.
 13. An electronic apparatus comprising: the physical quantity detection element according to claim 1; an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element; and a detection circuit that is configured to detect acceleration based on the detection signal.
 14. An electronic apparatus comprising: the physical quantity detection element according to claim 2; an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element; and a detection circuit that is configured to detect acceleration based on the detection signal.
 15. An electronic apparatus comprising: the physical quantity detection element according to claim 3; an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element; and a detection circuit that is configured to detect acceleration based on the detection signal.
 16. An electronic apparatus comprising: the physical quantity detection element according to claim 4; an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element; and a detection circuit that is configured to detect acceleration based on the detection signal.
 17. A moving object comprising: the physical quantity detection element according to claim 1; an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element; a detection circuit that is configured to detect acceleration based on the detection signal; and a controller that is configured to control an attitude of the moving object.
 18. A moving object comprising: the physical quantity detection element according to claim 2; an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element; a detection circuit that is configured to detect acceleration based on the detection signal; and a controller that is configured to control an attitude of the moving object.
 19. A moving object comprising: the physical quantity detection element according to claim 3; an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element; a detection circuit that is configured to detect acceleration based on the detection signal; and a controller that is configured to control an attitude of the moving object.
 20. A moving object comprising: the physical quantity detection element according to claim 4; an input circuit that inputs a detection signal according to physical quantity applied to the physical quantity detection element; a detection circuit that is configured to detect acceleration based on the detection signal; and a controller that is configured to control an attitude of the moving object. 